From your home screen, click on the "Accounts" tab. Scroll down, and if you have a Cc Pro Subscription, you will see text to "Cancel My Pro Subscription." If this text is not there, it means you have already cancelled your Pro Subscription.
If you have successfully cancelled, you will also see the buttons to try Cc Pro on the home page.
Note: As long as you cancel within 30 days of signing up for Cc Pro, you will not be charged! Contact us at firstname.lastname@example.org if you have any issues. Check out our cancellation policy for more information.